News tagged with human blood
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Blood is a specialized bodily fluid that delivers necessary substances to the body's cells — such as nutrients and oxygen — and transports waste products away from those same cells.
In vertebrates, it is composed of blood cells suspended in a liquid called blood plasma. Plasma, which comprises 55% of blood fluid, is mostly water (90% by volume), and contains dissolved proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), platelets and blood cells themselves. The blood cells present in blood are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes and platelets. The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates transportation of oxygen by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma as bicarbonate ion.
Vertebrate blood is bright-red when its hemoglobin is oxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin. Insects and some molluscs use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suffice for supplying oxygen.
Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system.
Blood is circulated around the body through blood vessels by the pumping action of the heart. In animals having lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled.
Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Ancient Greek word αἶμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue, given its origin in the bones and the presence of potential molecular fibers in the form of fibrinogen.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
The level of immunity to the recently circulating H7N9 influenza virus in an urban and rural population in Vietnam is very low, according to the first population level study to examine human immunity to the virus, which was ...
Diseases, Conditions, Syndromes 2 hours ago | not rated yet | 0 |
Raising hopes for cell-based therapies, UC San Francisco researchers have created the first functioning human thymus tissue from embryonic stem cells in the laboratory. The researchers showed that, in mice, ...
Immunology May 16, 2013 | 4.8 / 5 (5) | 0 |
Researchers have identified the dose of dengue virus in human blood that is required to infect mosquitoes when they bite. Mosquitoes are essential for transmitting the virus between people so the findings have important implications ...
Diseases, Conditions, Syndromes May 13, 2013 | not rated yet | 0 |
Infections can trigger hematopoiesis at sites outside the bone marrow – in the liver, the spleen or the skin. LMU researchers now show that a specific type of immune cell facilitates such "extra medullary" ...
Medical research May 16, 2013 | 5 / 5 (3) | 0
Children born with rare, inherited conditions known as Congenital Disorders of Glycosylation, or CDG, have mutations in one of the many enzymes the body uses to decorate its proteins and cells with sugars. Properly diagnosing ...
Genetics May 10, 2013 | 3 / 5 (1) | 0 |
Exposing skin to sunlight may help to reduce blood pressure, cut the risk of heart attack and stroke – and even prolong life, a study suggests.
Health May 07, 2013 | 5 / 5 (2) | 1
(Medical Xpress)—Organovo Holdings, Inc., a company that designs and creates functional human tissue has announced at this year's Experimental Biology Conference that it has developed a 3D printing technique ...
Medical research Apr 24, 2013 | 4.1 / 5 (8) | 0 |
A common nutritional supplement may be part of the magic in improving the survival rates of babies born with heart defects, researchers report.
Pediatrics May 08, 2013 | 5 / 5 (1) | 0
Taking a specific form of a vitamin E supplement can accelerate the health benefits that occur when people quit smoking, new research suggests. In the small study, improvement in blood vessel function associated with the ...
Health Apr 23, 2013 | 5 / 5 (2) | 0 |
A study in The Journal of General Physiology presents new methods to evaluate how astrocytes contribute to brain function, paving the way for future exploration of these important brain cells at unprecede ...
Medical research Apr 29, 2013 | not rated yet | 0